A sensitive determination of acetaminophen in pharmaceutical preparations and biological samples using multi-walled carbon nanotube modified glassy carbon electrode

Abstract

A chemically modified electrode is constructed based on multi-walled carbon nanotube modified glassy carbon electrode (MWCNTs/GCE). It was demonstrated that this sensor could be easily used for determination of acetaminophen (ACT) in aqueous buffered media. The measurements were carried out by application of differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CA) methods. Application of DPV method showed two linear dynamic ranges. The first linear dynamic range was from 0.1 to 22 μmol L -1, with a calibration equation of Ip(μA) = 1.2782c (μmol L-1) + 0.2431 (R2 = 0.9984) and the second linear dynamic range was between 26 to 340 μmol L-1 with a calibration equation of Ip(|xA) = 0.7793c (μmol L-1) + 11.615 (R2 = 0.9986). A detection limit of 0.029 μmol L-1 (S/N = 3) was obtained. The modified electrode showed electrochemical responses with high sensitivity, excellent selectivity and stability for ACT determination at optimal conditions, which makes it a suitable sensor for submicromolar detection of ACT in solutions. The analytical performance of this sensor has been evaluated for detection of ACT in human serum, human urine and a pharmaceutical preparation with satisfactory results. © 2011 Sociedade Brasileira de Química.